What do you think? Leave a respectful comment.

The video for this story is not available, but you can still read the transcript below.
No image

DNA’s 50th Anniversary

Margaret Warner discusses DNA with Eric Lander, director of the Whitehead Institute's Center for Genome Research in Cambridge, Massachusetts, and a representative of the Human Genome Project.

Read the Full Transcript

  • MARGARET WARNER:

    It was 50 years ago today that a pair of scientists, James Watson and Francis Crick, told the world they had unlocked the secret of the structure of DNA. DNA is the basic building block of life, a chemical molecule in the nucleus of virtually every cell that transmits the genetic code of one generation to the next. Watson and Crick published their news in the most modest of ways: With a one-page paper in the British Journal Nature. The report included a small illustration of the twisted ladder-like double helix structure they'd discovered.

    We get more on why that finding was so important then, and its ongoing implications, from a leading geneticist: Eric Lander. He's director of the Whitehead Institute-MIT Center for Genome Research, and one of the leaders of the Human Genome Project.

    Welcome Mr. Lander. Take us back to 1953 and tell us why this was such a big deal, this discovery, even at the time given where scientific understanding was.

  • ERIC LANDER:

    It was remarkable. This was the important question in biology in the 20s century. How do you explain heredity? How is it that organisms, parents transmit information to their children? Well, one day April 24, nobody knew and on April 25, it all became apparent. It all fell into place. And the answer was this beautiful structure of the DNA double helix. The secret was each strand was a copy of the other strand. And the way that information was copied was the two strands of the molecule came apart and each served as a template for the other. It was the greatest a-ha moment in science and it was 50 years ago today.

  • MARGARET WARNER:

    Tell us about these two guys, Crick and Watson.

  • ERIC LANDER:

    Well, if you were a betting person and you were trying to bet on the great horse race of who is going to discover the secret of life, you wouldn't have bet on Crick and Watson. They were about the oddest couple you could imagine. Jim Watson was a kid, 25 years old, came over from the United States to work in England where he was… he was interested in bird watching and things like that, had done a biology degree in the states.

    Francis Crick was 35. He was a physicist, hadn't done a thing in biology. He had worked in the British admiralty during War World II. And the two of them hooked up at the Cambridge Medical Council and they were going to crack the secret of life, the structure of DNA, and they were doing it up against the greatest scientists in the world at the time, the chemist Linus Pauling who was in hot pursuit and other people who were thinking about this as well. But in the end, when the dust settled, they were the people who figured out the simple and really beautiful secret.

  • MARGARET WARNER:

    And when they did, they knew it, didn't they?

  • ERIC LANDER:

    They knew it instantly. There are some discoveries where it takes a long time before the people who make them realize how important it was. But Jim Watson figured out in the morning, before lunchtime, that the As and Ts fit together in DNA, and the Cs and Gs fit together and consumed the same amount of space in the double helix, and by lunchtime they announced to the eagle pub and announced to everybody within ear shot, we found the secret of life. They very clearly knew it that day by lunchtime.

  • MARGARET WARNER:

    What is your theory about why this odd couple succeeded where other larger scientific figures hadn't?

  • ERIC LANDER:

    Well, I think they knew a secret, which was they talked a lot. They talked to each other incessantly about different ideas about how it might work and they listened a lot. They went down to London, for example, where they talked to Rosalind… they talked to Maurice Wilkins who showed them an x-ray photograph of Rosalind Franklin's and they absorbed that information, which turned out to contain a very important piece of the puzzle. That DNA was somehow helical. They listened, they read, but they just talked incessantly and they turned the problem over and over again.

    By contrast, someone like Linus Pauling, a very distinguished scientist, maybe he was too distinguished 24 his own good here. Pauling came up with, a few months before, a triple helical model for DNA that was absolutely patently wrong absolutely. It had the structure all backwards, couldn't possibly work, and yet somehow nobody told him. Maybe because he was so famous and such a good chemist nobody would point it out. Crick and Watson had just the right amount of audacity and obscurity and loquaciousness and they just pursued it doggedly. And they were also kind of lucky because if they hadn't discovered it, you can bet three or four months later others would have made the same discovery.

  • MARGARET WARNER:

    And they felt very much, did they not, that they were in a race?

  • ERIC LANDER:

    They knew they were completely in a race and were underdogs in a race because as so often happens in science, it was in the air. In the previous couple of years, it had become clear that DNA itself was the molecule of heredity and the big question was how, how in the world could some molecule encode heredity information? They knew. Although most people around them didn't really pick it up, but they knew this was the question for the century.

  • MARGARET WARNER:

    So what has their discovery meant already for science, biology, ands polling, genealogy, all these fields?

  • ERIC LANDER:

    Well, I mean, it has been just the unlocking of secrets in other possible direction — in medicine, in evolution, far more than Crick and Watson could have imagined. They've said as much in the course of this anniversary, that they knew it was an important thing, but they completely underestimated how far it would go. Once we realized that information was absolutely encoded in the sequence of letters of the DNA, a whole stream of discoveries flowed out over the course of the next couple of decades.

    We figured out how the cell actually encodes the instructions for making the proteins in our hair and our skin and in our blood, all in a certain genetic code. By the '60s, that code was known. By the '70s, the techniques common in DNA were worked out that let people propagate, clone pieces of DNA from human beings and bacteria and then very soon begin to work out their sequence. By the 1980s, it was possible to work out a few hundreds of letters of sequence in a day. And then people set their sights on the idea of reading out the three billion letters of the human genome. By the mid-1980s, the Human Genome Project was launched. And by last week, last Monday, the human genome project reached its completion, a double anniversary here with the DNA double helix when it announced the completion of the sequence, the finished sequence to the human genome.

    So we now have before us the instruction book for medicine. We have all the building blocks of a cell, and medical geneticists have been clawing all over this data to try to figure out what are the causes of diabetes and asthma and hypertension an the whole field of medicine is now focusing on molecular causes and molecular diagnostics and molecular therapies but at the same time it has unlocked the secrets of evolution because we can read the secret sequence of the human being, we can read the sequence of a mouse and line them up and see that they were the same text 57 million years ago and they've just changed a little bit here and there and we can characterize all the changes.

    By this summer, scientist will have the secrets of the chimpanzee genome and we can look at what happened in human history. And of course in law, both law enforcement officials and individuals who have been unjustly convicted have been able to use DNA information as some of the most powerful forensic tool for both convicting the guilty and exonerating the innocent. It's unimaginable.

  • MARGARET WARNER:

    M. Lander, I hate to cut you off. It has been wonderful. Thank you very much.

  • ERIC LANDER:

    Very happy DNA Day to you.

  • MARGARET WARNER:

    Thank you.

The Latest